Impossible to publish: failed to prepare local package for uploading

[contactomorph]

Problem

When trying to publish my crate:

PS C:\repos\tensorism> cargo publish -vv
    Updating crates.io index
   Packaging tensorism v0.1.0 (C:\repos\tensorism)
   Archiving
error: failed to prepare local package for uploading

Caused by:
  failed to open for archiving: `C:\repos\tensorism`

Caused by:
  Access is denied. (os error 5)

Notes

I tried to publish it from a friend's machine, suspecting the problem was related to something about my local environment but I got exactly the same error.

Version

cargo 1.67.0-nightly (f6e737b1e 2022-12-02)
release: 1.67.0-nightly
commit-hash: f6e737b1e3386adb89333bf06a01f68a91ac5306
commit-date: 2022-12-02
host: x86_64-pc-windows-msvc
libgit2: 1.5.0 (sys:0.15.0 vendored)
libcurl: 7.86.0-DEV (sys:0.4.59+curl-7.86.0 vendored ssl:Schannel)
os: Windows 10.0.19045 (Windows 10 Pro) [64-bit]

[weihanglo]

Not exactly the same issue but probably you can follow this to investigate #11544.

[ehuss]

This is caused by having an empty readme field in Cargo.toml:

[package]
name = "foo"
version = "0.1.0"
readme = ""

This also happens with license-file = "".

I think the solution is to generate a better error message when readme or license-file is set to an empty string.

[kylematsuda]

@rustbot claim

[kylematsuda]

Hi! So the problem seems to be the following lines from the build_ar_list function for license-file (and a similar section below that for readme):

cargo/src/cargo/ops/cargo_package.rs

Lines 281 to 293 in be33892

	if let Some(license_file) = &pkg.manifest().metadata().license_file {
	let license_path = Path::new(license_file);
	let abs_file_path = paths::normalize_path(&pkg.root().join(license_path));
	if abs_file_path.exists() {
	check_for_file_and_add(
	"license-file",
	license_path,
	abs_file_path,
	pkg,
	&mut result,
	ws,
	)?;
	} else {

If license-file = "", then abs_file_path points at the crate root and the abs_file_path.exists() check is true, leading to abs_file_path being added to the archive list. The error then occurs later when tar is eventually called, which expects a file for license-file instead of a directory.

A simple fix could be to change Path::exists to Path::is_file. This would also catch the case where an existing directory is provided for license-file, for example license-file = "./src" (which currently causes the same error as license-file = "").

Does that approach sound okay? The same change (+ adding a helpful warning message) should also work for readme.

[ehuss]

That sounds good to me!